Cygnus

Cyg star chart (IAU and Sky & Telescope magazine, Roger Sinnott & Rick Fienberg).

One of the 88 IAU constellations.

Etymology and History

Cyg, Lyr, Del, Aql and Sge on the Kugel Globe (1st century BCE), SMH 2024.

The Greek constellation was originally named "The Bird" (ornithos).

Origin of Constellation

Greco-Roman

Aratus

[275] Yes, there is even a dappled Bird accompanying Zeus, hazy in some parts, while other parts on it bristle with stars, not very bright, though still not dim. Just like a bird in fair-weather flight, it glides on the breeze towards the horizon, stretching its right wing-tip in the direction of Cepheus’ right hand, [281] while close to its left wing lies the prancing Horse. (Kidd 1997)

Hyginus, Astronomica

The sign the Greeks call the Swan, but others, out of ignorance of the story, have called it ornis, the general term for bird. This reason for the name has been handed down: When Jupiter, moved by desire, had begun to love Nemesis, and couldn't persuade her to lie with him, he relieved his passion by the following plan. He bade Venus, in the form of an eagle, pursue him; he, changed to a swan, as if in flight from the eagle, took refuge with Nemesis and lighted in her lap. Nemesis did not thrust him away, but holding him in her arms, fell into a deep sleep. While she slept, Jupiter embraced her, and then flew away. Because he was seen by men flying high in the sky, they said he was put in the stars. To make this really true, Jupiter put the swan flying and the eagle pursuing in the sky. But Nemesis, as if wedded to the tribe of birds, when her months were ended, bore an egg. Mercury took it away and carried it to Sparta and threw it in Leda's lap. From it sprang Helen, who excelled all other girls in beauty. Leda called her her own daughter. Others say that Jove, in the form of a swan, lay with Leda. We shall leave the matter undecided. (Mary Ward 1960)

Almagest Ὅρνες (Bird).

id	Greek (Heiberg 1898)	English (Toomer 1984)	ident.
	Ὅρυιθος ἀστερισμός.	Constellation of Cygnus
1	ὁ ἐπὶ τοῦ στόματος.	The star on the beak	bet Cyg
2	ὁ τούτῳ ἐπόμενος καὶ ἐπὶ τῆς κεφαλῆς.	The one to the rear of this, on the head	phi Cyg
3	ὁ ἐν μέσῳ τῷ τραχήλῳ	The star in the middle of the neck	eta Cyg
4	ὁ ἐν τῷ στήθει	The star in the breast	gam Cyg
5	ὁ ἐν τῇ οὐρᾷ λαμπρός	The bright star in the tail	alf Cyg
6	ὁ ἐυ τῷ ἀγκῶνι τῆς δεξιᾶς πτέρυγος	The star in the bend of the right wing	del Cyg
7	τῶν ἐκ τῷ δεξιῷ ταρσῷ ἡ’ ὁ νότιος	The southernmost of the 3 in the right wing-feathers	tet Cyg
8	ὁ μέσος τῶν τριῶν	The middle one of the three	iot Cyg
9	ὁ βόρειος αὐτῶν καὶ ἐπ’ ἄκρου τοῦ ταρσοῦ	The northernmost of them, on the tip of the wing-feathers	kap Cyg
10	ὁ ἐπὶ τοῦ ἀγκῶνος τῆς ἀριστερᾶς πτέρυγος	The star on the bend of the left wing	eps Cyg
11	ὁ βορειότερος αὐτῶν καὶ ἐν μέσῃ τῇ αὐτῇ πτέρυγι	The star north of this, in the middle of the same wing	lam Cyg
12	ὁ ἐν ἄκρῳ τῷ ταρσῷ τῆς ἀριστερᾶς πτέρυγος	The star in the tip of the feathers of the left wing	zet Cyg
13	ὁ ἐπὶ τοῦ ἀριστεροῦ ποδός	The star on the left leg	nu Cyg
14	ὁ ἐπὶ τοῦ ἀριστεροῦ γόρατος.	The star on the left knee	xi Cyg
15	τῶν ἐν τῷ δεξιῷ ποῦὶ β ὁ προηγούμευος	The more advanced of the 2 stars in the right leg	omi1 Cyg
16	ὁ ἐπόμενος αὐτῶν	The one to the rear	omi2 Cyg
17	ὁ ἐπὶ τοῦ δεξιοῦ γόνατος νεφελοειδής.	The nebulous star on the right knee	ome Cyg
	ὁ ἀστέρες ἰς, ὥν β’ μεγέθους α, γ’ ἔ, δ’ 3, ε’ β.	17 stars, 1 of the second magnitude, 5 of the third, 9 of the fourth, 2 of the fifth
	Οἱ περὶ αὐτὸν ἀμόρφωτοι.	Stars around [Cygnus] outside the constellation
18	τῶν ὑπὸ τὴν ἀριστερὰν πτέρυγα ᾑ ὁ νοτιώτερος.	The southernmost of the 2 stars under the left wing	tau Cyg
19	ὁ βορειότερος αὐτῶν	The northernmost of them	sig Cyg
	ἀστέρες β μεγέθους ὀ΄.	2 stars of the fourth magnitude

Transfer and Transformation of the Constellation

• 

  Cygnus in Fortin's Atlas Céleste, 3rd edition (1795).

References

• References (general)
• References (Babylonian)
• References (ancient Greco-Roman)
• References (medieval)